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Attention, dieters: If you want to maximize your chances of success, don’t go to the grocery
store on an empty stomach.

So says a new JAMA Internal Medicine study from two members of the Cornell University Food and
Brand Lab, where researchers investigate “the psychology behind what people eat and how often they
eat it.”

Study authors Brian Wansink and Aner Tal asked 68 people to fast for five hours before reporting
to the lab for the experiment. Then they were asked to do their grocery shopping in a simulated
online store. The e-market offered low-calorie items such as produce and lean chicken as well as
high-calorie products, including candy and salty snacks. Each junk-food item was displayed along
with a more healthful alternative. (One difference between the simulated store and a real store: No
prices were displayed.)

Half of the study subjects were offered Wheat Thins crackers to snack on before they logged into
the store. These shoppers wound up putting about eight low-calorie items into their shopping carts,
on average: 2.44 snacks, 1.56 dairy items, 2.81 grocery items and 0.95 meats. They also made about
four high-calorie selections, on average.

The rest of the study subjects did their grocery shopping with rumbling tummies. These shoppers
also selected about eight low-calorie items, on average: 2.84 snacks, 1.40 dairy items, 2.80
grocery items and 1.20 meats. But these shoppers also put an average of about six high-calorie
foods into their shopping carts.

Would that difference hold up in real life? To find out, the Cornell researchers tracked
purchases of 82 shoppers in a grocery store. Those who went shopping in the after-lunchtime slot
between 1 and 4 p.m. bought an average of 11.2 low-calorie items and 2.69 high-calorie items, for a
ratio of nearly 4 to 1. In contrast, people who went shopping in the pre-dinner time slot between 4
and 7 p.m. — when they were more likely to be hungry — put an average of 8.21 low-calorie items in
their baskets, along with 3.81 high-calorie items, for a ratio of nearly 2.5-to-1.